Oil repellent textile finish

ABSTRACT

Polyfluoro alkyl esters of polymeric phosphonitrilic acid (Formula I) having average molecular weights in the range of 5,000-10,000, a method for making the polymers, and the use of the polymers in oil and water repellent finishes for cellulosic textile materials.   Rf is a perfluoroalkyl group of at least two carbon atoms, preferably of at least three carbon atoms, and n is the number of units required for an average molecular weight between 5,000 and 10,000.

United States Patent 1 1.

Stackel et al.

1 51 Feb. 27, 1973 OIL. REPELLENT TEXTILE FINISH [75] Inventors: Richard Frederick Stackel; George Robert Depaolo, both of Bridgewater Township, Somerset County, NY.

[73] Assignee: American Cyanamid Company,

Stanford, Conn.

[22] Filed: April 23, 1970 [21] Appl. No.: 43,301

Related US. Application Data [62] Division of Ser. No. 678,180, Oct. 26, 1967, Pat. No.

3,304,198 2/1967 Woolf et a1. ..l17/143 A 5/1968 Pittman et a1 ..1 17/121 UX 3,419,602 12/1968 Pittman et al. ..1 17/121 X 3,479,214 11/1969 Pittman et a1. ..117/l21 X Primary Examiner-William D. Martin 4 Assistant ExaminerTheodore G. Davis Attorney-Charles J. Fickey [57] ABSTRACT Polyfluoro alkyl esters of polymeric phosphonitrilic acid (Formula 1) having average molecular weights in the range of 5,000-10,000, a method for making the polymers, and the use of the polymers in oil and water repellent finishes for cellulosic textile materials.

(BCHZR! n R, is a perfluoroalkyl group of at least two carbon atoms, preferably of at least three carbon atoms, and n is the number of units required for an average molecular weight between 5,000 and 10,000.

3 Claims, No Drawings OIL REPELLENT TEXTILE FINISH This is a divisional of application Ser. No. 678,180, filed Oct. 26, 1967, now U. S. Pat. No. 3,524,907.

This invention relates to a new class of polymeric fluoro compounds of use as textile finishes. More particularly, it relates to (l) polyfluoro alkyl esters of polymeric phosphonitrilic acid (Formula I) having average molecular weights in the range of 5,000-10,000, (2) to a method for making the polymers, and (3) to the use of the polymers in oil and waterrepellent finishes for cellulosic textile materials.

CHzRl 00mm I R is a perfluoroalkyl group of at least two carbon atoms, preferably of at least three carbon atoms, and n is the number of units required for an average molecular weight between 5,000 and 10,000.

There has been a marked increase in the commercial use of fluoro chemicals which impart water and oil repellency to textiles. The Scotchgard (3M Company) and Zepel (du Pont Company) brands of fluoro chemicals have acquired a considerable use in oil repellent and stain resistant finishes for textiles.

However, it has been learned that not all fluoro chemicals will impart water and oil repellency when applied to fabric. There are a number of conditions that must be satisfied to produce an effective textile finish. A major consideration is the need for a fluorinated carbon chain evenly distributed on the fibers, with proper orientation of the perfluoro groups to present an essentially fluorinated surface to the water and oil. Of the many ways of obtaining these conditions, one of the most successful is the incorporation of the fluorinated molecule into a polymer in which the perfluoro groups constitute the side chains.

In general, the properties desired in fabrics treated with fluoro chemicals include oil repellency, water repellency, durability to laundering and durability to dry cleaning. There is a continuing need for improved fluoro chemical textile finishes.

It is therefore an object of this invention to provide a fluoro compound suitable in a textile finish to provide oil repellency, water repellency and durability to both laundering and dry cleaning.

This and other objects of the invention will become apparent as the description thereof proceeds.

A new class of polymeric fluoro compounds has now been discovered which have superior properties as durable oil repellent finishes for cellulosic textile materials.

The polymers may be represented by Formula I, i.e., they are polyfluoro alkyl esters of polymeric phosphonitrilic acid. The method of preparation is novel and unobvious. The average molecular weight of the polymeric esters is within the range of 5,000 to 10,000.

{beat RrCHzONa CHZRI 1:

Wpes or classes of polymeric esters of phosphonitrilic acid are known. Both types can be prepared from polymeric phosphonitrilic chloride, of which the trimer (formula Ila) is the most common form.

The preparation of the two known types of polymeric fluoro compounds are shown in reactions (1 and (2).

There are two steps in reaction (1). In the first step, the phosphonitrilic chloride trimer (Ila) is heated in a sealed tube under carefully controlled conditions. Separation of the polymeric products gives a relatively low yield of uncrosslinked polymer (llb). The uncrosslinked polymer is then reacted with a polyfluoro alkoxide ion obtained from an alkali metal salt of a polyfluoro alcohol to give a polymeric ester (III) which has a very high molecular weight (about 1,000,000) and is very insoluble in most solvents. (Inorg. Chem. 5, 1709 (1966)). The low yield and insolubility of the products are disadvantages to their use as oil repellents.

In reaction (2), the trimer (Ila) is reacted with an alkali metal salt of a polyfluoro alcohol to give a trimeric product (IV). (US. Pat. No. 2,876,247). The products are moderately active as oil repellents, but they are not durable to laundering; Also, they have no water-repellency.

The polymeric fluoro compounds of this invention (I) are excellent oil repellents with good durability to laundering and dry cleaning. They also have moderately good water repellency that is also durable to laundering and dry cleaning. The products have solubility in organic solvents and may be applied to textile materials from such solutions.

The polymers (1) are obtained by the novel reaction (3). In this reaction, trimeric phosphonitrilic chloride (Ila), or other halide, is contacted with a polyfluoro alcohol of the formula R CI-I Ol-I in the presence of a tertiary amine. Without the tertiary amine, the desired products are not obtained.

Suitable polyfluoro alcohols are, R,CH OI-I, where R, is a fluorinated carbon chain having from two to 20 carbon atoms in the chain, preferably from three to 10 carbon atoms. Representative alcohols include 1,1-I-I,H- pentafluoropropanol (R, is pentafluoroethyl), l,l-H,H- heptafluorobutanol (R is heptafluoropropyl), l,1-I-I,H- pentadecafluorooctanol (R, is pentadecafluoroheptyl), and the like.

In the formula, n represents a polymeric length giving a molecular weight between 5,000 to 10,000.

Suitable amines include both tertiary alkylamines and heterocyclic amines with tertiary nitrogen atoms. Tertiary alkylamines which may be used have for example from one to 20 or more carbon atoms, preferably from one to 12 carbon atoms, in the alkyl radicals. Examples are trimethyl, triethyl, tripropyl, triisopropyl, tributyl, triisobutyl, tridecyl and the like, amines also suitable are alkylene diamines such as tetraalkylalkylene diamines, for example tetramethylethylenediamines, and polyalkylene polyamines where all nitrogen atoms are tertiary nitrogen atoms.

Also useful are heterocyclic amines having one or more tertiary nitrogen atom in the ring such as pyridine, quinoline, and the like, including those substitited with substituents which do not interfere with the reaction, such as the lutidines, picolines, and the like.

Although stoichiometric proportions of polyfluoro alcohol and phosphonitrilic halide may be used, it is advantageous to use an excess of the alcohol. The amount of tertiary amine used is not critical, providing, at least sufficient to bind the liberated hydrogen chloride is used. It is advantageous to employ a liquid tertiary amine, such as pyridine, as the solvent medium for the reaction, although other solvents can be used, if desired.

The temperature of reaction is not critical. The reaction can be carried out conveniently at room temperature, or at temperatures above and below room temperature, for example from about to about 100C.

Conventional methods are used to isolate the polymeric product, such as by pouring the reaction mixture into water or dilute acid and separating the oily product. The yield of product is close to 100 percent of theory. No purification steps are required.

The products (I) are distinguished from those of Formula IV by molecular weight.

The products (I) are distinguished from those of Formula V by molecular weight, infrared absorption (IR) and nuclear magnetic resonance (NMR) measurements.

The products (I) are soluble in solvents such as acetone and dimethylformamide. They can be applied to textile materials from such solutions, or from aqueous dispersions or emulsions, by standard padding procedures well known in the textile field.

The polymers may be used as oil repellents on cellulosic textile materials, including cotton, viscose rayon, and the other cellulosic fibers. They are also useful on blends of cellulosic fibers with other fibers such as polyesters (Dacron), polyamides (nylon), etc.

The finish can be dried on the fabric or it can be dried and cured. Often curing is beneficial, particularly with respect to water repellency. Curing temperatures in the range of 150 to 200C. or higher may be used.

In the following examples, swatches of the treated fabrics, initially, after laundering and after dry cleaning, are tested by standard procedures for oil and water repellency.

Laundering is carried out in a home type washing machine using a detergent in the water.

The dry cleaning is carried out according to standard procedures with a commercial dry cleaning fluid.

The oil repellency is measured by the published 3M oil repellency test, whereby drops of various mixtures of mineral oil and n-heptane (see following table) are placed on the fabric and allowed to stand for three minutes. The number corresponding to the mixture containing the highest percentage of heptane which does not penetrate or wet the fabric is considered the oil repellency rating of the fabric.

Repellency Mineral n-Heptane Rating Oil 1 50 0 100 140 10 90 1 30 20 80 l 20 30 l 1 0 40 60 100 50 50 90 60 40 8O 7O 3O 70 20 6O 10 50 0 0 (no hold-out to mineral oil Experience has shown close correlation between oil repellency values and resistance to liquid oily stains. The fabrics with ratings of 50-70 will exhibit only fair resistance to staining; those fabrics with ratings of 80-90 will show good resistance to staining; and those with ratings of 100 and above will show excellent resistance.

The water repellency ratings are spray ratings and are measured by standard test method AATCC 22-1964, as published in the Technical Manual of the American Association of Textile Chemists and Colorists. A rating of 90-100 is considered excellent, 80 is good and 70 is fair.

The following specific examples are given to illustrate the invention and are not intended to be limitative.

A mixture of 7.0 g. (0.02 mole) of trimeric phosphonitrilic chloride and 24 g. (0.12 mole) of 1,1- H,H-heptafluoro-n-butanol and 40 ml. of pyridine was stirred at 20-25C. for 24 hours. The solution was poured into dilute hydrochloric acid and the oily layer was washed with water. The product was the bis(l,l- H,H-heptafluorobutyl) ester of polymeric phosphonitrilic acid. The IR, NMR and molecular weight measurements indicate a mixture of polymeric esters with molecular weights within the range of 5,000-10,000.

EXAMPLE 2 [NP(OCH CF CF n A solution of 7.0 g. (0.02 mole) of trimeric phosphonitrilic chloride and 18 g. (0.12 mole) of 1,1- l-l,H-pentafluoro-n-propanol in 40 ml. of pyridine was stirred at 20-25C. for 24 hours. The solution was poured into dilute hydrochloric acid, and the oily layer was washed with water. The product was the bis( 1 ,1- H,H-pentafluoropropyl) ester of polymeric phosphonitrilic acid. Analytical data indicate that the product is a mixture of esters with molecular weights within the range of 5,000-10,000.

A solution of 1.75 g. (0.005 mole) of phosphonitrilic chloride and 10.0 g. (0.025 mole) of l,l-l-l,H-pentadecafluorooctanol and 25 ml. of pyridine was stirred at 20-25C. for 48 hours. The solution was poured into water, and the oily layer was separated and dried. The product is the bis( 1 ,l-H,H-pentadecafluorooctyl) ester EXAMPLE 4 A suspension of 56 g. of phosphorous pentachloride in 100 ml. of tetrachloroethane was added during 30 minutes to a mixture of 6.2 g. of phosphorous pentachloride, 17.6 g. of ammonium chloride and 100 ml. of tetrachloroethane at the reflux temperature and the refluxing was continued for hours. The solvent was evaporated and the residue (28.5 g.) was dissolved in 52 ml. of pyridine.

A portion of the solution (40 g.), equivalent to 14.3 g. (0.122 mole) of polymeric phosphonitrilic chloride, was cooled, and 40 g. (0.244 mole) of l,1-H,Il-heptafluoro-n-butanol was added, and the mixture was stirred for about 15 hours. The mixture was then poured into water, and the organic layer was separated, washed with water and dried.

The analytical data indicate that the product is a mixture of fluorobutyl esters of polymeric phosphonitrilic acid.

EXAMPLE 5 A 5 percent solution of bis(l,l-I-I,H-heptafluoro-nbutyl) ester of polymeric phosphonitrilic acid (product of Example 1) in dimethylformamide was applied to 80 X 80 cotton percale at 4 percent of polymer o.w.f. (on the weight of the fabric) by a standard procedure. The fabric was dried in air at room temperature, and a portion of the dried fabric was then heated in an oven at 175C. for 1.5 minutes.

The results of the tests for oil and water repellency are shown in Table I.

The procedure of Example 5 was repeated using bis( 1 ,-l-H,H-pentafluor0-n-propyl) ester of polymeric phosphonitrilic acid (product of Example 2).

The test results are shown in Table II.

TABLE II Ratings Oil Repellency Dried Only Dried and Cured Initial 80 80 Laundered 60 60 Dry Cleaned 8O 80 Water Repellency Initial 0 70 Laundered 0 70 Dry Cleaned 50/0 70 EXAMPLE 7 The procedure of Example 5 was repeated substituting bis( 1 ,1-H,H-pentadecafluorooctyl) ester of polymeric phosphonitrilic acid (product of Example 3).

The test results are shown in Table III.

TABLE III Rating Oil Repellency Dried Only Dried and Cured Initial 100 l 10 Laundered Dry Cleaned 90 90 Water Repellency Initial 0 0 Laundered 0 0 Dry Cleaned 50 50 EXAMPLE 8 The procedure of Example 5 was repeated using the ester product of Example 4.

The test results are shown in Table IV.

TABLE IV Rating Oil Repellency Dried Only Dried and Cured Initial l 10 Laundered 100 l 00 Dry Cleaned 100 90 Water repellency Initial 0 7O Laundered 0 5 0 Dry Cleaned 3O 70 n O CHiRi AGHQRI 11 wherein R, is a perfluoroalkyl radical of from three to 10 carbon atoms and n is the number of units required for an average molecular weight between 5,000 and 10,000 and thereafter drying the material and curing the polymer thereon by heating the material at a temperature between and 200C.

2. An oil repellent cellulosic textile material comprising a cellulosic textile material treated with a polymer of the structure:

0 CHzRr wherein R, is a perfluoroalkyl radical of from three to 10 carbon atoms and n is the number of units required for an average molecular weight between 5,000 and 10,000.

3. A composition for treating cellulosic textile materials comprising a polymeric fluoro compound of the formula 

2. An oil repellent cellulosic textile material comprising a cellulosic textile material treated with a polymer of the structure:
 3. A composition for treating cellulosic textile materials comprising a polymeric fluoro compound of the formula 